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Search: id:A157754
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| 0, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 1, 4, 1, 2, 1, 2, 1, 1, 1, 3, 2, 1, 3, 2, 1, 1, 1, 5, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 4, 2, 2, 1, 2, 1, 3, 1, 3, 1, 1, 1, 2, 1, 1, 2, 6, 1, 1, 1, 2, 1, 1, 1, 6, 1, 1, 2, 2, 1, 1, 1, 4, 4, 1, 1, 2, 1, 1, 1, 3, 1, 2, 1, 2, 1, 1, 1, 5, 1, 2, 2, 2
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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a(n) for n >= 2 equals LCM of minimal and maximal exponents in prime factorization of n. a(n)for n >= 2 it deviates from (A072411), first different term is a(360), a(360) = 3, A072411(360)= 6.
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FORMULA
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a(1) = 0, a(p) = 1, a(pq) = 1, a(pq...z) = 1, a(p^k) = k, for p = primes (A000040), pq = product of two distinct primes (A006881), pq...z = product of k (k > 2) distinct primes p, q, ..., z (A120944), p^k = prime powers (A000961(n) for n > 1) k = natural numbers (A000027).
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EXAMPLE
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For n=12=2^2*3^1 the a(12)=LCM(2,1)=2.
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CROSSREFS
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Cf. A000040, A006881, A120944, A000961, A000027, A072411, A051904, A051903.
Sequence in context: A070013 A070014 A051903 this_sequence A072411 A091050 A005361
Adjacent sequences: A157751 A157752 A157753 this_sequence A157755 A157756 A157757
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KEYWORD
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nonn
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AUTHOR
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Jaroslav Krizek (jaroslav.krizek(AT)atlas.cz), Mar 05 2009
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